Grassland forages are naturally rich in phytochemicals such as (poly)phenols and terpenoids, yet most studies to date have focused on easily liberated, abundant compounds, thus overlooking less abundant and cell wall-bound phytochemicals. As a result, species-specific (poly)phenol profiles in common grassland forages remain poorly characterised. This study addresses that gap by profiling the (poly)phenolic and antioxidant content in free and bound fractions of five temperate forage species: plantain ( Plantago lanceolata ), timothy ( Phleum pratense ), chicory ( Cichorium intybus ), white clover ( Trifolium repens ), and red clover ( Trifolium pratense ). Plantain exhibited the highest total phenolic content (TPC) (26.98 mg GAE/g DW) and TFC (17.08 mg QE/g DW), while chicory showed the greatest ABTS •+ activity (18.46 mg TE/g DW), and white clover showed the highest FRAP activity (25.86 mg TE/g DW). LC-MS/MS revealed substantial phytochemical diversity. In total, 58 distinct (poly)phenols were identified, including several compounds not previously reported in these forage species. Leguminous plants (red clover and white clover) possessed the highest number of quantifiable (poly)phenols (≥ 22 compounds), compared with ≤ 16 in the non-leguminous forage species. Principal component analysis (PCA) distinguished species-specific (poly)phenolic markers: cyanidin in red clover, chicoric acid in chicory, protocatechuic acid in timothy, caffeic acid in plantain, and catechin derivatives in white clover. These species-specific phytochemical fingerprints provide a practical basis for forage authentication and indicate that grassland forages as a novel reservoir of naturally sourced antioxidants.
Kearney et al. (2026) studied this question.